Composition of ex vivo perfusion solutions and kinetics define differential cytokine/chemokine secretion in a porcine cardiac arrest model of lung preservation.

Background: Ex vivo lung perfusion (EVLP) uses continuous normothermic perfusion to reduce ischemic damage and to improve post-transplant outcomes, specifically for marginal donor lungs after the donation after circulatory death. Despite major efforts, the optimal perfusion protocol and the composition of the perfusate in clinical lung transplantation have not been identified. Our study aims to compare the concentration levels of cytokine/chemokine in different perfusion solutions during EVLP, after 1 and 9 h of cold static preservation (CSP) in a porcine cardiac arrest model, and to correlate inflammatory parameters to oxygenation capacities. Methods: Following cardiac arrest, the lungs were harvested and were categorized into two groups: immediate (I-EVLP) and delayed EVLP (D-EVLP), after 1 and 9 h of CSP, respectively. The D-EVLP lungs were perfused with either Steen or modified Custodiol-N solution containing only dextran (CD) or dextran and albumin (CDA). The cytokine/chemokine levels were analyzed at baseline (0 h) and after 1 and 4 h of EVLP using Luminex-based multiplex assays. Results: Within 4 h of EVLP, the concentration levels of TNF-α, IL-6, CXCL8, IFN-γ, IL-1α, and IL-1ß increased significantly (P < 0.05) in all experimental groups. The CD solution contained lower concentration levels of TNF-α, IL-6, CXCL8, IFN-γ, IL-2, IL-12, IL-10, IL-4, IL-1RA, and IL-18 (P < 0.05) compared with those of the Steen solution. The concentration levels of all experimental groups have correlated negatively with the oxygenation capacity values (P < 0.05). Protein concentration levels did not reach statistical significance for I-EVLP vs. D-EVLP and CD vs. CDA solutions. Conclusion: In a porcine cardiac arrest model, a longer period of CSP prior to EVLP did not result in an enhanced protein secretion into perfusates. The CD solution reduced the cytokine/chemokine secretion most probably by iron chelators and/or by the protecting effects of dextran. Supplementing with albumin did not further reduce the cytokine/chemokine secretion into perfusates. These findings may help in optimizing the preservation procedure of the lungs, thereby increasing the donor pool of organs.

Porcine slaughterhouse lungs for ex vivo lung perfusion - a pilot project.

Ex vivo lung perfusion (EVLP) is an emerging technique for evaluation and eventual reconditioning of donor lungs. Before clinical use experiments with laboratory animals are standard. It was the aim of this study to compare lungs evaluated with EVLP from laboratory animals with slaughterhouse lungs and to investigate the potential use of a slaughterhouse lung model for ex vivo lung perfusion as an alternative for the use of laboratory animals. In a porcine model of Donation after Circulatory Determination of Death (DCDD) 16 lungs were obtained either from regular slaughterhouse animals (SL n = 8) or from laboratory animals in organ procurements (SS n = 8). Lungs were flushed and stored cold for four hours in Perfadex Plus™ and subsequently perfused ex vivo with Steen Solution™ for up to four hours. During 4 hours of EVLP lung functional parameters and activities of lactate, lactate dehydrogenase (LDH) and alkaline phosphatase (AP) in the perfusate were recorded hourly. Histological samples were taken and evaluated fur Lung Injury. Lungs showed no significant difference in oxygen capacity in between groups (∆ PO2 averaged over 4 hours: SL 293 ± 187 mmHg SS 247 ± 199 mmHg). LDH concentration was significantly higher in slaughterhouse lungs (SL 438,5 ± 139,8 U/l, SS 258,42 ± 108,4 U/l P ≤ 0,01). We conclude that the use of slaughterhouse lungs for EVLP was feasible with no significant disadvantages compared to standard organ procurement lungs regarding lung functional outcomes. With the use of slaughterhouse lungs animal experiments in EVLP research could be successfully reduced.

Use of modified Custodiol-N as perfusion solution in ex vivo lung perfusion.

OBJECTIVES: Ex vivo Lung Perfusion (EVLP) is a promising tool to increase the donor pool for lung transplantation. Custodiol-N solution was originally designed for organ preservation during cold static preservation (CSP) and was successfully used for machine perfusion in kidneys. It was the aim of this study to compare the lung functional outcomes after 4 hours of EVLP using modified Custodiol-N or STEEN SolutionTM as perfusion solution. METHODS: In a porcine DCD model, lungs were perfused either with STEEN SolutionTM (Standard SS, n=8) or modified Custodiol-N with added 1.1 g/l glucose monohydrate and 50 g/l dextran 40 (CD, n=8). For a third group 7 g/l albumin was supplemented to modified Custodiol-N (CDA, n=8). During four hours of EVLP pulmonary gas exchange and activities of lactate dehydrogenase (LDH) and alkaline phosphatase (AP) in perfusate were recorded. RESULTS: Lungs that underwent EVLP with modified Custodiol-N showed significantly higher oxygen capacity (ΔpO2 averaged over four hours of EVLP: SS: 236.28 ± 47.26 mmHg, CD: 402.79 ± 30.33 mmHg, CDA: 414.86 ± 9.77 mmHg) than lungs perfused with STEEN SolutionTM. The addition of albumin did not have a significant effect on lung function but these lungs showed lower wet/dry ratio. CONCLUSION: In a porcine DCD model of 9 hours CSP followed by four hours of EVLP the use of modified Custodiol-N as perfusion solution was feasible and associated with higher oxygen capacity than STEEN SolutionTM. The addition of albumin seems to further stabilize lung function.

Effects of immediate versus delayed ex-vivo lung perfusion in a porcine cardiac arrest donation model.

OBJECTIVE: Ex-vivo lung perfusion is a promising tool to evaluate and recondition marginal donor lungs usually after a cold static preservation. The concept of continuous organ perfusion is supposed to reduce ischemic damage; however, the optimal perfusion protocol has not been established yet. The aim of this study was to compare immediate ex-vivo lung perfusion (I-EVLP) to delayed ex-vivo lung perfusion (D-EVLP) after a certain cold static preservation period on lung function in a large animal model. METHODS: In a porcine model, lungs were procured after circulatory death and 60 min of no-touch warm ischemia. Lungs were preserved with single-flush cold low potassium dextran solution and prepared either for I-EVLP (n = 8) or stored cold for 9 h with subsequent D-EVLP (n = 8). Functional outcomes and morphology were compared during 4 h of ex-vivo lung perfusion, using STEEN SolutionTM as perfusion solution. RESULTS: Pulmonary functional data, perfusate activities of lactate dehydrogenase, alkaline phosphatase, and products of lipid peroxidation did not differ significantly. There was a trend toward lower wet-dry ratio (I-EVLP: 13.4 ± 2.9; D-EVLP: 9.1 ± 2.5) and higher ΔpO2 in D-EVLP group (I-EVLP: 209 ± 51.6 mmHg; D-EVLP: 236.3 ± 47.3 mmHg). CONCLUSION: In this donation-after-circulatory-death model, 9 h of cold static preservation followed by ex-vivo lung perfusion results in comparable pulmonary function to I-EVLP as indicated by oxygenation capacities and wet-dry ratio. Our findings indicate that prolonged cold static preservation prior to ex-vivo lung perfusion is as safe and effective as I-EVLP in the procurement of donor lungs.

One-year experience with ex vivo lung perfusion: Preliminary results from a single center.

OBJECTIVE: To enlarge the donor pool for lung transplantation, an increasing number of extended criteria donor lungs are used. However, in more than 50% of multi-organ donors the lungs are not used. Ex vivo lung perfusion offers a unique possibility to evaluate and eventually recondition the injured donor lungs. The aim of our study was to assess the enlargement of the donor pool and the outcome with extended criteria donor lungs after ex vivo lung perfusion. PATIENTS AND METHODS: Data were prospectively collected in our lung transplant database. We compared the results of lung transplants after ex vivo lung perfusion with those after conventional cold static preservation. In total, 11 extended criteria donor lungs processed with ex vivo lung perfusion and 41 cold static preservation lungs transplanted consecutively between May 2016 and May 2017 were evaluated. Normothermic ex vivo lung perfusion was performed according to the Toronto protocol for 4 h. Cold static preservation lungs were stored in low-potassium dextran solution. RESULTS: Ex vivo lung perfusion lungs before procurement had significantly lower PaO2/FiO2 (P/F) ratios and more X-ray abnormalities. There were no statistically significant differences for pre-donation ventilation time, smoking history, or sex. After reconditioning with ex vivo lung perfusion, 9 out of 11 processed lungs were considered suitable and successfully transplanted. The mean postoperative ventilation time and in-hospital stay were not significantly different in ex vivo lung perfusion and cold static preservation recipients. CONCLUSION: Ex vivo lung perfusion can safely be used in the evaluation of lungs initially considered not suitable for transplantation. The primary outcome was not negatively affected and normothermic ex vivo lung perfusion is a useful tool to increase the usage of potentially transplantable lungs.